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Author Margueron, Samuel ♦ Pokorny, Jan ♦ Skiadopoulou, Stella ♦ Kamba, Stanislav ♦ Liang, Xin ♦ Clarke, David R.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ BRILLOUIN ZONES ♦ CONCENTRATION RATIO ♦ DIELECTRIC MATERIALS ♦ ELECTRIC CONDUCTIVITY ♦ ELECTRON GAS ♦ ELECTRONS ♦ INDIUM OXIDES ♦ INTERFACES ♦ NANOSTRUCTURES ♦ PERIODICITY ♦ PHONONS ♦ PLASMONS ♦ POLARIZATION ♦ RAMAN EFFECT ♦ REFLECTIVITY ♦ SUPERLATTICES ♦ TWO-DIMENSIONAL SYSTEMS ♦ ZINC OXIDES
Abstract A thermodynamically stable series of superlattices, (ZnO){sub k}In{sub 2}O{sub 3}, form in the ZnO-In{sub 2}O{sub 3} binary oxide system for InO{sub 1.5} concentrations from about 13 up to about 33 mole percent (m/o). These natural superlattices, which consist of a periodic stacking of single, two-dimensional sheets of InO{sub 6} octahedra, are found to give rise to systematic changes in the optical and vibrational properties of the superlattices. Low-frequency Raman scattering provides the evidence for the activation of acoustic phonons due to the folding of Brillouin zone. New vibrational modes at 520 and 620 cm{sup −1}, not present in either ZnO or In{sub 2}O{sub 3}, become Raman active. These new modes are attributed to collective plasmon oscillations localized at the two-dimensional InO{sub 1.5} sheets. Infrared reflectivity experiments, and simulations taking into account a negative dielectric susceptibility due to electron carriers in ZnO and interface modes of the dielectric layer of InO{sub 2}, explain the occurrence of these new modes. We postulate that a localized electron gas forms at the ZnO/InO{sub 2} interface due to the electron band alignment and polarization effects. All our observations suggest that there are quantum contributions to the thermal and electrical conductivity in these natural superlattices.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-05-21
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 119
Issue Number 19


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